G-PROTEIN MUTATIONS IN TUMORS OF THE PITUITARY, PARATHYROID AND ENDOCRINE PANCREAS

A subset of growth-hormone (GH) producing pituitary adenomas harbour m utations at residues Arg201 and Gln227 of the alpha subunit of the sti mulatory G protein (G(s) alpha). One such mutation has been reported i n a GH-producing tumour from a patient with multiple endocrine neoplas ia type 1 (MEN 1) although mutations have not been reported in other t umours associated with MEN 1. We used PCR-induced restriction site ana lysis to screen for these mutations in 80 tumours of the pituitary, pa rathyroid and endocrine pancreas. Arg201 mutations were detected in 1 non-functioning and 4 GH-producing pituitary tumours. No mutations wer e found in any of the endocrine tumours tested at Arg179 of the G(i2)a lpha subunit, a homologous residue to Arg201 of G(s) alpha. Our result s indicate oncogenesis in the majority of pituitary and parathyroid tu mours is independent of mutations of G(s) and G(i2) alpha. (C) 1995 Ac ademic Press, Inc.